This is an application for competitive renewal of a program project grant which has been active for 29 years. It involves many investigators and many different projects all relating to the improve of the results of organ transplantation. The basic overall OBJECTIVES of this grant have been to: (A) Analyze and isolate the clinical problems involved in organ transplantation and precisely document clinical laboratory correlations. (B) Organize clinical trials based on available data to solve clinical problems. (C) Generate experimental approaches to help solve clinical problems. Within these objectives, all projects are organized into two essential AIMS: AIM 1: TO PREVENT ORGAN DESTRUCTION. This includes not only immunological manipulations designed to prevent rejection but also those designed to prevent non-immunologic graft loss, to prolong patient survival, and to modify or control drug toxicity and recurrent disease. AIM 2: TO MAXIMIZE REHABILITATION. The focus here is on minimizing complications and maximizing compliance with the immunosuppressive regimen. Within this framework, the current applications include projects addressing late mortality (1 project), chronic graft loss (4 projects), defining risk factors (1 project), and decreasing morbidity 5 projects. The 2 Cores--Clinical and Administrative-support all projects.